1. Field of the Invention
This invention relates to a sealing structure of an accessory module in which a casing, containing an accessory (e.g. an on-vehicle CCD camera) and a board, and wires, which are to be connected thereto, can be releasably connected together by the use of a ; connector, and besides a sealing performance is enhanced.
2. Related Art
Conventional camera modules Y and Z will be described with reference to FIGS. 7 to 10. FIG. 7 is an enlarged view of a portion of a wire harness 4 on which a clamp 50 with on O-ring 51 is mounted. A wire harness will be described briefly. Generally, a bundle of wires, used for connection to those electrical circuits of an automobile or the like except high-voltage circuits and an ignition circuit, is called a wire harness. Here, however, it means a wiring bundle comprising wiring elements (including wires) which are bundled together so that the mounting of wires or the like can be easily effected in an assembly line for automobiles. The wire harness is also called a wiring harness.
The O-ring 51, shown in FIG. 7, is provided on the clamp 50 so as to keep the interior of a camera casing 3 in an air-tight condition when the clamp 50 is attached to the camera casing 3. A clamp is a part used for mounting cables, such as a wire harness, on a mating structural object such as an automobile, and here it means a fastening member for fixedly mounting the relevant part.
The clamp 50 includes a threaded portion 50a for positively fixing this clamp to the camera casing 3, a hexagonal head 50b used when fixing the clamp 50 to the camera casing 3 by a thread-tightening operation, and a flange portion 50c which produces a force to fasten the clamp 50 and the camera casing 3 together, and also plays an important role in a sealing function of the O-ring 51.
A passage hole 50d for passing wires, such as cables 4a and 4axe2x80x2, therethrough is formed in the clamp 50. As shown in FIG. 7, the wires 4a and 4axe2x80x2, such as cables 4a and 4axe2x80x2 (including the drain wire 4axe2x80x2), are passed through the passage hole 50d in the clamp 50 with the O-ring 51, and terminals TL1, that is, terminal members TL1, are secured to distal ends of the cables 4a and 4axe2x80x2, respectively. The terminals TL1 are received in a connector housing, and in this manner a connector CR1 is formed at the distal end of the wire harness 4 as shown in FIG. 8. The terminal designates a terminal member, and means an electrode.
The connector housing will be described briefly, and the connector housing is an electrically-insulating part which holds the terminals, that is, the terminal members, in a suitable arrangement pattern, and has the function of insulating the terminals from one another or from other conductors. Generally, the connector housing has receiving chambers in which the terminals or the like are mounted. The connector means apart for the purpose of achieving an electrical connection, and is provided with electrical connection parts, such as terminals and wires.
After the cables 4a and 4axe2x80x2 are passed through the passage hole 50d in the clamp 50 shown in FIG. 7, a potting processing PG is applied to this clamp. Here, the potting processing PG will be described briefly, and it means a process of pouring soft rubber, such as an epoxy polymer, or a soft resin into a predetermined portion to seal it.
By thus applying the potting processing PG, even each of the cables 4a and 4axe2x80x2 can be completely sealed so that the intrusion of moisture, dust, dirt and so on into the interior of the camera casing 3 and the interior of a camera 1 can be prevented. The confirmation of the sealing performance of the thus potting-applied portion is made by an operation for confirming the air-tightness and liquid-tightness by water leakage.
FIGS. 8 and 9 are a perspective view showing the manner of assembling the camera modules Y, Z provided with the conventional on-vehicle CCD camera 1. The camera module Y, provided with the conventional on-vehicle CCD camera, will be described briefly, and the camera module Y mainly comprises the camera 1, such as an on-vehicle CCD camera, and a board 2 on which this camera 1 is mounted. The camera module Z comprises the camera module Y, having the camera 1 mounted on the board 2, the camera casing 3 on which this camera module Y is mounted, and the wire harness 4 comprising the wires 4a and 4axe2x80x2 bundled together.
FIGS. 8 and 9 show the process of assembling the conventional on-vehicle CCD, and FIG. 9 is a perspective view specifically showing troubles encountered when mounting the camera module Y, comprising the camera 1 and the board 2, on the camera casing 3. FIG. 10 is a cross-sectional view taken along the line Rxe2x80x94R of FIGS. 8 and 9, and also is a conceptual view showing an object to which the wire harness 4 is connected, and more specifically this figure is an enlarged, cross-sectional view showing a condition in which the wire harness 4 is mounted on the camera casing 3 through the clamp 50.
Here, a CCD will be described briefly, and the CCD mainly designates a charged-coupled device, and more specifically means a device which converts an optical signal, representing an image or the like, into an electrical signal by the use of a semiconductor device responsive to light. The CCD is an abbreviation of xe2x80x9cCharge Coupled Devicexe2x80x9d, and is a semiconductor made public in 1977 by Bell Laboratory of U.S.A. Generally, the picture quality of the CCD is mostly determined by the number of pixels, and the number of pixels of CCDs is set to the wide range of from several hundreds of thousands to several millions. It is surmised that the number of pixels is further increasing so as to meet the requirements made from now on.
CCDs have been extensively used in cameras, such as a digital camera and a video camera, and a facsimile machine, a scanner and a duplicating machine or a copying machine such as a laser beam printer. In the case of a digital camera, a CCD is provided at a focus portion instead of a silver salt film. Recently, CCDs, having a large number of pixels, have become inexpensive, and have much Contributed to the low-cost and high picture quality of digital cameras.
The parts of the conventional camera module Z, shown in FIGS. 8 to 10, will be described in detail, and first, the camera 1 mainly comprises a lens 1c, and a lens periphery portion 1d for fixing the lens 1c, as shown in FIGS. 8 and 9. Next, the board 2, on which the camera 1 is mounted, mainly comprises a board body 2xe2x80x2, and electrical parts (such as connectors) for electrical connection are mounted on this board body 2xe2x80x2.
A connector CR2 is provided at the board 2 of the camera module Y provided with the CCD camera 1. A connector housing of the connector CR2, which is a kind of electrical associated part, is secured to the board body 2xe2x80x2 by fastening elements such as screws. A total of four mounting holes 2b, used for fixedly securing the board 2 to the camera casing 3 by screws SC1 or the like, are formed respectively in those portions of the board body 2xe2x80x2 disposed adjacent respectively to four corners thereof.
The camera casing 3 is formed by a bottom wall 3c and side walls 3d and 3dxe2x80x2 provided respectively at four sides of this bottom wall in surrounding relation thereto, so that a receiving chamber 3e is formed. A cylindrical projected portion 3h, which performs the function of fixing the clamp 50 and also the function of sealing the interior of the camera casing 3, is formed on the side wall 3dxe2x80x2. Screw-fixing bodies 3a, to which the board 2, provided with the camera 1, is adapted to be fixedly secured, are provided respectively at four corners of the receiving chamber 3e of the camera casing 3, and an internally-threaded screw hole 3b is formed in each of the screw-fixing bodies 3a. 
The condition of mounting of the clamp 50 on the camera casing 3, shown in FIGS. 8 and 9, will be described in detail with reference to FIG. 10, and a through hole 3f for passing the wire harness 4, comprising the bundle of cables 4 and 4xe2x80x2, therethrough is formed through the side wall 3dxe2x80x2 of the camera casing 3. An internally-threaded groove for threaded engagement with the threaded portion 50a of the clamp 50 to positively fix this clamp is formed in an inner peripheral surface of the through hole 3f. 
The clamp 50 (shown in FIG. 7), having the cables 4a and 4axe2x80x2 passed therethrough, is mounted in the through hole 3f formed through the side wall 3dxe2x80x2 of the camera casing 3. The threaded portion 50a of the clamp 50 is threadedly engaged in the through hole 3f of the camera casing 3, which is processed to have the threads, so that the clamp 50, having the wire harness 4 passed therethrough, is fixed to the camera casing 3 as shown in FIG. 10.
The cylindrical projected portion 3h is formed around the periphery of the through hole 3f in the camera casing 3 so that the clamp 50, provided with the above-mentioned O-ring 51, can be properly guided into the through hole 3f through this projected portion, and can be mounted therein. The cylindrical projected portion 3h maintains the air-tight condition, formed by the O-ring 51 mounted on the clamp 50, thus performing the function of a screen plate for preventing the intrusion of moisture, dust, dirt and so on from the exterior.
As shown in FIG. 10, the camera casing 3 is electrically connected by the wire harness 4 to a non-waterproof connector CR3 provided within a vehicle room V. A terminal TL2 is secured to one end of the drain wire 4a branching off from an intermediate portion of the wire harness 4, and the terminal TL2 is secured to a frame of a vehicle body B by a screw SC2. Thus, the drain wire 4axe2x80x2 performs the function of an earth.
As shown also in FIGS. 8 and 9, the connector CR1, comprising the connector housing in which the terminals, connected respectively to the cables 4a and 4axe2x80x2, are inserted, is connected to the connector CR2, provided at the board 2, in a male-female manner to form the male and female connectors, so that the cables 4a and 4axe2x80x2 are electrically connected to the camera 1 such as an on-vehicle CCD camera. In this manner, the board 2, provided with the camera 1, is electrically connected to the wire harness 4 and the non-waterproof connector CR3 within the vehicle room V, and the electrical connection of the drain wire 4axe2x80x2 is also made.
Grommets (not shown) are mounted on the wire harness 4 intermediate the opposite ends thereof. A grommet is an annular part made of rubber which protects a wire harness, a tube, a hose, a cable or the like from an edge portion of a through hole portion, formed in a vehicle body, a casing of a part or others, and is also used for the purpose of insulating dust, sound and so on. Because of its waterproof and dust-insulating nature, the grommet also functions as a sealing member. Grommets are used when passing a wire harness from a vehicle room to the exterior of the vehicle or when passing a wire harness from the vehicle room into an engine room or a trunk room.
One example of a method of assembling the on-vehicle CCD camera, shown in the prior art, will be described below in detail. First, the clamp 50, provided with the O-ring 51, is mounted on the wire harness 4 shown in FIG. 10. Then, the wire harness 4, comprising the bundle of cables 4a and 4axe2x80x2, is passed through the passage hole 50d in the clamp 50, thereby provisionally fixing the wire harness 4 and the clamp 50 to each other.
That portion of a tube 4d (which protects the cables 4a and 4axe2x80x2, and bundles them together), which is to extend beyond the clamp 50 into the camera casing 3, is cut by a knife or the like, so that the cables 4a and 4axe2x80x2 are taken out of the tube 4d. The terminals TL1 are already secured to the distal ends of the cables 4a and 4axe2x80x2, and these terminals TL1 are received in the connector housing to form the connector CR1 shown in FIG. 8.
In order to enhance the sealing between the wire harness 4 and the clamp 50 in this condition, the potting processing PG is applied by pouring a resin or rubber into the passage hole 50d in the clamp 50, thereby fixing the two together as shown in FIG. 7. The air-tightness within the camera casing 3 can be enhanced by the potting processing PG shown in FIGS. 7 and 10.
The above-mentioned operation for assembling the wires 4 and the peripheral parts of the wires 4 together will be called the assembly of the wire harness 4 and the connector, or may be merely called the connector assembly (assembly will be called xe2x80x9cASSYxe2x80x9d in an abbreviated manner). In this case, the cables 4a and 4axe2x80x2 have a somewhat extra length as shown in FIGS. 8 and 9 so that these cables can connected the camera casing 3 to the board 2. Thus, the clamp 50 is fixed to the predetermined portion of the wire harness 4.
Next, the clamp 50, through which the cables 4a and 4axe2x80x2 have been passed as described above, is mounted in the through hole 3f in the camera casing 3. The threaded portion 50a of the clamp 50 with the O-ring 51 is threaded into the through hole 3f, that is, the internally-threaded hole, in the camera casing 3, thereby fixing the clamp 50 to the camera casing 3 as shown in FIGS. 8 to 10. At this time, the air-tightness and sealing performance within the camera casing 3 are maintained by the O-ring 51 and the potting processing PG as shown in FIG. 10.
After the preparations are thus made, the board 2, having the camera 1 mounted thereon, that is, the camera module Y, is mounted on the camera casing 3. With respect to the procedure of this assembly, first, the connector CR1, provided at the wire harness 4, is connected to the connector CR2, provided at the board body 2xe2x80x2, to form the male and female connectors, as shown in FIGS. 8 and 9.
After the above-mentioned connectors are connected, the camera module Y is mounted on the camera casing 3. In this mounting method, first, the camera module Y, including the camera 1 and the board 2, is attached to the camera casing 3 in such a manner that the mounting holes 2b, formed in the board 2, are aligned respectively with the internally-threaded screw holes 3b provided respectively at the four corners of the camera casing 3.
Then, each screw SC1 is passed through the corresponding mounting hole 2b formed in the board body 2xe2x80x2, and is screwed and tightened by screw fastening means. As a result, the screw SC1 is screwed into the internally-threaded screw hole 3b provided at the camera casing 3. In this manner, the board 2, provided with the camera 1, that is, the camera module Y, is fixedly secured to the camera casing 3, thus assembling the camera module Z.
With respect to peripheral techniques, there are disclosed JP-A-9-245880, JP-A-10-144385, JP-A-10-172643, JP-A-10-172644, JP-A-10-172645, JP-A-7-42075U and so on.
JP-A-9-245880 describes a relay connector for positively preventing a leakage of an oil liquid at a terminal insertion portion. JP-A-10-144385 describes improvements in drip-proof performance, moisture-proof performance and attaching/detaching operability of a wiring connector for a shelf illumination lamp incorporated in a showcase.
JP-A-10-172643 describes a waterproof connector for an electronic control unit in which the alignment of terminals can be easily secured, and the reflow soldering can be effected easily, and the good waterproof performance can be obtained. JP-A-10-172644 describes a waterproof connector for an electronic control unit in which the height of a male connector can be reduced, and the number of component parts can be reduced. JP-A-10-172645 describes a waterproof connector for an electronic control unit in which a male connector can be formed into a compact size, and a good appearance can be obtained.
JP-A-7-42075U describes a connector connecting apparatus. JP-A-7-42075U describes the connector connecting apparatus, in which conductors of a plurality of pair wires of a cable are automatically arranged on a provisionally-retaining cover of a connector, and an arrangement holding mechanism for automatically arranging the pair wires in a row without changing the order of combination of the pair wires.
However, in the above conventional camera module Z shown in FIGS. 8 and 9, when assembling this camera module Z, there was needed the operation in which the cables 4a and 4axe2x80x2 were passed from the exterior of the camera casing 3 into the receiving chamber 3e of the camera casing 3 through the through hole 3f (see FIG. 10) in the camera casing 3.
And besides, in order to enhance the sealing performance of the through hole 3f in the camera casing 3, there was needed the operation in which the clamp 50, mounted on the wire harness 4, was screwed into the threaded portion of the through hole in the camera casing 3, and was fastened to the camera casing 3.
Furthermore, there was needed the operation in which the connector CR1, secured to the distal ends of the cables 4a and 4axe2x80x2, was connected to the connector CR2, mounted on the board 2, in a male-female manner to make the electrical connection. Therefore, the assembling operation of the camera module Z must depend on manual operations, and therefore the workers were required to perform the complicated assembling operations. Thus, many complicated operations were needed for assembling the conventional camera module Z, and much production tact and production time were required, and this was not efficient from the viewpoint of productivity.
FIG. 9 is a perspective view showing troubles encountered when mounting the camera module Y on the camera casing 3. There was a fear that when mounting the conventional camera module Y on the camera casing 3, the cables 4a and 4axe2x80x2 were caught between the camera module Y and the camera casing 3 as shown in FIG. 9.
There was a fear that the conductors in the cable 4a or the drain wire 4axe2x80x2, caught between the camera module Y and the camera casing 3 in the assembling process, were cut, and therefore the camera module Z, having such cable 4a or drain wire 4axe2x80x2, must be treated as a defective product.
However, it is not desirable to discard such semi-finished products from the viewpoint of the global environment, and besides this is wasteful from the viewpoint of production, and therefore it was necessary to re-assemble the camera module Z while changing the wire harness 4 (including the cables 4a, the drain wire 4axe2x80x2 and the tube 4d) and those parts relevant to the wires 4, such as the clamp 50.
Besides the above catching problem that the cables 4a and 4axe2x80x2 were caught, the conventional camera module Z was not complete with respect to the waterproof measures. In the conventional camera module Z, the interior of the camera casing 3 was formed into the sealing structure, using the clamp 50, mounted on the wire harness 4, and so on, and the connector CR1, provided at the distal end of the wire harness 4 spaced from this clamp 50, was connected to the connector CR2, mounted on the board 2, in a male-female manner, thereby electrically connecting the wire harness 4 to the various electrical circuits on the board 2.
The camera module Z is thus formed into the sealing structure so as to prevent moisture from intruding into the camera 1. However, in the camera module Z shown in FIG. 8, any sealing measures are not provided at the connector CR2, mounted on the board 2, and the connector CR1 secured to the distal ends of the cables 4a and 4axe2x80x2. 
For example, if a cut W is accidentally formed in that portion of the tube 4d of the wire harness 4 extending outwardly from the camera module Z as shown in FIG. 10, and this cut reaches the conductors in the cable 4a, 4axe2x80x2 through an insulating sheath thereof, then rain water or the like intrudes into the camera module Z through the interior of the cable 4a, 4axe2x80x2. Therefore, there was a fear that various troubles could develop in the camera module Z.
FIG. 6 is an enlarged, cross-sectional view of the cables 4a and 4axe2x80x2 bundled together in the wire harness 4. The cable 4a, 4axe2x80x2 comprises a plurality of conductors 4b and the insulating sheath 4c, and provides the conductor cable, and very small gaps 4bxe2x80x2 are seen between the conductors 4b. 
When rain water or the like intrudes into the cable 4a, 4axe2x80x2 through the above-mentioned cut W, the rain water advances forward along the cable 4a, 4axe2x80x2 because of a capillary action of the very small gaps 4bxe2x80x2, existing between the plurality of conductors 4b bundled together in the cable 4a, 4axe2x80x2, and finally reaches the connectors CR1 and CR2 of the camera module Z shown in FIG. 9, and therefore there was a fear that the moisture intruded into the camera module Z.
A CCD camera is composed of precise electronic parts and mechanical parts, and therefore unless the camera module Z, having such a CCD camera mounted thereon, was completely maintained in a sealed condition relative to the exterior, there was a fear that there occurred various troubles such as an electrical trouble and the development of a cloud on the lens 1c of the camera 1.
More specifically, the troubles, which would be caused by the intrusion of the moisture into the camera module Z, are various problems such as the development of rust on the metallic parts, the incomplete electrical contact and the short-circuiting caused by the moisture, and the development of a cloud on the lens 1c by the condensation of the moisture, which prevents the satisfactory photographing.
It has been thought that these problems can be solved by applying waterproof measures to both of the connector CR2, provided at the board 2 of the camera module Z, and the connector CR1, secured to the distal ends of the cables 4a and 4axe2x80x2, thus forming these connectors into a waterproof connector. However, even if merely the waterproof connector is adopted in the camera module Z, the above catching problem still remains unsolved, and besides the following problems still remain unsolved.
When carrying out a maintenance operation for the camera 1, it has heretofore been necessary to recover the whole of the camera module Z including the wire harness 4, and much time and labor have been required for this recovering operation. Even if it is intended to effect the recovering operation for the camera module Z, including the wire harness 4, or to recycle and re-use the camera module Z in view of the global environment when a failure of the camera module Z occurs, many difficulties are involved in the above recovering operation when considering the contents of various operations required for recovering the camera module Z having the wire harness 4 connected thereto, and actually it has been thought impossible to carry out the recovering operation for the camera module Z.
In view of the above points, it is an object of this invention to provide a sealing structure of an accessory module in which a casing, containing an accessory, such as a camera, and a board, and wires, which are to be connected to this casing, can be easily connected together and disconnected from each other by the use of connectors, thereby solving the problem that the wires, such as cables, are caught between the camera casing and the board when assembling the conventional accessory module, and besides foreign matters, such as moisture, dust and dirt, are prevented from intruding into the interior of the accessory module, thereby enhancing a sealing performance.
Another object is to provide a sealing structure of an accessory module in which a casing, containing an accessory, and wires can be easily separated from each other so that the disassembly, inspection, repair and etc., of an accessory and its neighboring portions can be easily effected, thus providing an excellent maintenance performance.
The above objects have been achieved by a sealing structure of an accessory module of the present invention characterized in that an accessory is mounted on a board; and a connector main portion is formed by terminals and a connector board; one end portions of the terminals are soldered to the board; a first sealing member is provided at the connector main portion; an inner housing, corresponding to the connector main portion, is formed within a receiving chamber of a casing; a connector frontage portion is formed at the casing; and by mounting the board on the casing, the first sealing member is held in intimate contact with the inner housing to seal the connector frontage portion, and also a connector is formed.
Effectively, the other end portions of the terminals project toward an opening of the connector frontage portion, and insertion holes, corresponding respectively to the terminals, are formed through the first sealing member, and the terminals are press-fitted into the insertion holes, respectively, and the first sealing member is held in intimate contact with the connector board.
Effectively, a second sealing member is provided at a front portion of a mating connector secured to a cable, and when the mating connector and the connector are coupled together, the two are electrically connected together, and also a front surface portion of the mating connector is held in intimate contact with the first sealing member provided at the connector, and also the second sealing member, provided at the mating connector, is held in intimate contact with the inner housing of the casing to seal the connector.
Effectively, at least one lip, comprising at least one ridge, is formed on at least one surface of the first sealing member, the lip enhancing a sealing performance of the surface.
Effectively, by attaching a cover to the casing, a mating surface of the casing and a mating surface of the cover are abutted against each other, so that the accessory is sealed within the receiving chamber of the casing or a receiving chamber of the cover.
Effectively, a camera module is formed by using a camera, adapted to be mounted on an automobile, as the accessory.
FIG. 1 is an exploded, perspective view of one preferred embodiment of an accessory module of the invention.
FIG. 2 is an exploded, perspective view of the accessory module.
FIG. 3 is a view of the accessory module in its assembled condition.
FIG. 4 is an enlarged, perspective view showing a condition in which a connector frontage portion is sealed by a first sealing member.
FIG. 5 is a longitudinal cross-sectional view of the accessory module.
FIG. 6 is an enlarged cross-sectional view of a cable.
FIG. 7 is an enlarged view of a portion of a wire harness having a clamp mounted thereon.
FIG. 8 is a perspective view of a conventional camera module which is in the process of being assembled.
FIG. 9 is a perspective view specifically showing troubles encountered when mounting the camera module on a camera casing.
FIG. 10 is an enlarged, cross-sectional view taken along the line Rxe2x80x94R of FIGS. 8 and 9, and also is a conceptual view showing an object to which a wire harness is connected.